Preliminary Research On Local Path Planning For Unmanned Surface Vehicle

Path planning is an important part of research in Unmanned Surface Vehicle(USV).When sailing at sea,USV needs to avoid obstacles adaptively for its characteristics of high-speed and intelligent.USV path planning includes global path planning and local path planning.In general,it uses the static method based on electronic chart to realize the global path planning.When USV sails at sea with high-speed,dynamic local path planning based on sensors is more important,and to meet the"International Regulations for Preventing Collisions at sea,1972" is difficult.Therefore,to do the research on local path planning for USV meeting the "International Regulations for Preventing Collisions at sea,1972" is of great significance.In this paper,the main work is as follows:1.The existing path planning methods and their advantages and disadvantages are summarized and analyzed.By reviewing and analyzing the path planning for USV,the path planning is divided into global path planning based on marine environmental information and local path planning based on sensor information from the way to get the obstacle information.2.According to the "International Regulations for Preventing Collisions at sea,1972",combining with the characteristics of small size and high speed of USV,the encounter situation of USV is divided quantitatively with its position as the original point and its heading 000°.The collision risk models which are suitable for USV are established based on the close-range encounter models of ships.3.The multi-objective genetic algorithm of local path planning for USV is designed.The shortest path and minimum change of course are the optimization goals and the close-range encounter models of ships are the constraints.The tournament selection operator based on rank allocation and crowed distance is used to do the genetic manipulation.When obstacles and paths segments intersect with each other,the point repairing method based on definite proportionate inserted point method and discriminant method is presented.4.The model and algorithm of local path planning for USV is verified.The head-on situation,crossing situation and multiple ships situation with static obstacles are designed to do the simulation verification based on MATLAB R2015b platform.The results show that USV can avoid multiple obstacles and find the optimal path to meet the model and algorithm.It shows that the method of local path planning for USV presented in this paper is feasible and effective.